Scanning Electron Microscopy Investigation for Monitoring the Emulsion Deteriorative Process and Its Applications in Site-Directed Reaction with Paper Fabric

The O/W isocyanate emulsion can be used as a sizing agent to improve the waterproof performance of paper. However, the -NCO content in the emulsion diminishes with the prolongation of standing time. What is happening to this seemingly stable emulsion, especially concerning its microstructure evoluti...

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Autores principales:	Liewei Qiu, Yongkang Zhang, Xueli Long, Zhi Ye, Zhangmingzu Qu, Xiaowu Yang, Chen Wang
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	morphological change deteriorative monitoring SEM investigation site-directed reaction sizing treatment Organic chemistry QD241-441
Acceso en línea:	https://doaj.org/article/19b3bf8a7e364099af37ab843b74f726
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spelling	oai:doaj.org-article:19b3bf8a7e364099af37ab843b74f7262021-11-11T18:28:42ZScanning Electron Microscopy Investigation for Monitoring the Emulsion Deteriorative Process and Its Applications in Site-Directed Reaction with Paper Fabric10.3390/molecules262164711420-3049https://doaj.org/article/19b3bf8a7e364099af37ab843b74f7262021-10-01T00:00:00Zhttps://www.mdpi.com/1420-3049/26/21/6471https://doaj.org/toc/1420-3049The O/W isocyanate emulsion can be used as a sizing agent to improve the waterproof performance of paper. However, the -NCO content in the emulsion diminishes with the prolongation of standing time. What is happening to this seemingly stable emulsion, especially concerning its microstructure evolution? We propose to monitor the emulsions deteriorative process by combining freeze-drying technique and SEM. Thus, the emulsion containing -NCO active group was obtained by the synthetic polymer emulsification of HDI trimers. The results of SEM demonstrate that the emulsion deteriorative process actually represents the collapsing and fusion of stable honeycomb structure with the prolongation of standing time and increasing temperature. This is possibly due to the fact that the inner aggregative HDI trimers are reacting with outside water to form urethane macromolecules, and this results in the collapsing and fusion of the honeycomb structure, as observed in SEM images. Moreover, the measurement results of -NCO content and FT-IR spectroscopy present the -NCO content as reducing with increasing standing time and temperature. This conclusion further proves our hypotheses. Additionally, the emulsions are used to treat the paper by site-directed reaction. The results show that the with the increase of the standing time and temperature, the contact angles and surface free energy show a decrease and an increase, respectively, whereas surface free energy appeared at a minimum of 29.19 mJ·m<sup>−2</sup> when the standing time and temperature was 1 h and 25 °C.Liewei QiuYongkang ZhangXueli LongZhi YeZhangmingzu QuXiaowu YangChen WangMDPI AGarticlemorphological changedeteriorative monitoringSEM investigationsite-directed reactionsizing treatmentOrganic chemistryQD241-441ENMolecules, Vol 26, Iss 6471, p 6471 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	morphological change deteriorative monitoring SEM investigation site-directed reaction sizing treatment Organic chemistry QD241-441
spellingShingle	morphological change deteriorative monitoring SEM investigation site-directed reaction sizing treatment Organic chemistry QD241-441 Liewei Qiu Yongkang Zhang Xueli Long Zhi Ye Zhangmingzu Qu Xiaowu Yang Chen Wang Scanning Electron Microscopy Investigation for Monitoring the Emulsion Deteriorative Process and Its Applications in Site-Directed Reaction with Paper Fabric
description	The O/W isocyanate emulsion can be used as a sizing agent to improve the waterproof performance of paper. However, the -NCO content in the emulsion diminishes with the prolongation of standing time. What is happening to this seemingly stable emulsion, especially concerning its microstructure evolution? We propose to monitor the emulsions deteriorative process by combining freeze-drying technique and SEM. Thus, the emulsion containing -NCO active group was obtained by the synthetic polymer emulsification of HDI trimers. The results of SEM demonstrate that the emulsion deteriorative process actually represents the collapsing and fusion of stable honeycomb structure with the prolongation of standing time and increasing temperature. This is possibly due to the fact that the inner aggregative HDI trimers are reacting with outside water to form urethane macromolecules, and this results in the collapsing and fusion of the honeycomb structure, as observed in SEM images. Moreover, the measurement results of -NCO content and FT-IR spectroscopy present the -NCO content as reducing with increasing standing time and temperature. This conclusion further proves our hypotheses. Additionally, the emulsions are used to treat the paper by site-directed reaction. The results show that the with the increase of the standing time and temperature, the contact angles and surface free energy show a decrease and an increase, respectively, whereas surface free energy appeared at a minimum of 29.19 mJ·m<sup>−2</sup> when the standing time and temperature was 1 h and 25 °C.
format	article
author	Liewei Qiu Yongkang Zhang Xueli Long Zhi Ye Zhangmingzu Qu Xiaowu Yang Chen Wang
author_facet	Liewei Qiu Yongkang Zhang Xueli Long Zhi Ye Zhangmingzu Qu Xiaowu Yang Chen Wang
author_sort	Liewei Qiu
title	Scanning Electron Microscopy Investigation for Monitoring the Emulsion Deteriorative Process and Its Applications in Site-Directed Reaction with Paper Fabric
title_short	Scanning Electron Microscopy Investigation for Monitoring the Emulsion Deteriorative Process and Its Applications in Site-Directed Reaction with Paper Fabric
title_full	Scanning Electron Microscopy Investigation for Monitoring the Emulsion Deteriorative Process and Its Applications in Site-Directed Reaction with Paper Fabric
title_fullStr	Scanning Electron Microscopy Investigation for Monitoring the Emulsion Deteriorative Process and Its Applications in Site-Directed Reaction with Paper Fabric
title_full_unstemmed	Scanning Electron Microscopy Investigation for Monitoring the Emulsion Deteriorative Process and Its Applications in Site-Directed Reaction with Paper Fabric
title_sort	scanning electron microscopy investigation for monitoring the emulsion deteriorative process and its applications in site-directed reaction with paper fabric
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/19b3bf8a7e364099af37ab843b74f726
work_keys_str_mv	AT lieweiqiu scanningelectronmicroscopyinvestigationformonitoringtheemulsiondeteriorativeprocessanditsapplicationsinsitedirectedreactionwithpaperfabric AT yongkangzhang scanningelectronmicroscopyinvestigationformonitoringtheemulsiondeteriorativeprocessanditsapplicationsinsitedirectedreactionwithpaperfabric AT xuelilong scanningelectronmicroscopyinvestigationformonitoringtheemulsiondeteriorativeprocessanditsapplicationsinsitedirectedreactionwithpaperfabric AT zhiye scanningelectronmicroscopyinvestigationformonitoringtheemulsiondeteriorativeprocessanditsapplicationsinsitedirectedreactionwithpaperfabric AT zhangmingzuqu scanningelectronmicroscopyinvestigationformonitoringtheemulsiondeteriorativeprocessanditsapplicationsinsitedirectedreactionwithpaperfabric AT xiaowuyang scanningelectronmicroscopyinvestigationformonitoringtheemulsiondeteriorativeprocessanditsapplicationsinsitedirectedreactionwithpaperfabric AT chenwang scanningelectronmicroscopyinvestigationformonitoringtheemulsiondeteriorativeprocessanditsapplicationsinsitedirectedreactionwithpaperfabric
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Scanning Electron Microscopy Investigation for Monitoring the Emulsion Deteriorative Process and Its Applications in Site-Directed Reaction with Paper Fabric

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